bnxt_en: Support RSS contexts in ethtool .{get|set}_rxfh()

Support up to 32 RSS contexts per device if supported by the device.

Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20240325222902.220712-11-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>